1. Field of the Invention
This invention relates to a human reproduction indexing device for indicating the calender dates for days of a menstrual cycle on which the probability of conception is the greatest.
2. Description of the Prior Art
Timing is a very important consideration for those couples who want to have a baby as well as those who wish to practice some method of birth control. In particular, they must know the days of a menstrual cycle on which the probability of conception is the greatest. While it is generally known that there are a limited number of days during each month on which a woman can become pregnant, i.e. one to two days following ovulation, couples are often imprecise in guessing the fertile time because of misunderstandings as to the time of occurrance of ovulation, and how to predict when ovulation should occur.
There are a number of indirect methods for determining the time of ovulation. The method most frequently employed is the Basal body temperature (BBT) method which is based upon detection of the rise of a woman's body temperature that occurs around, or soon after the time of ovulation. However, the need to take and record daily temperatures is an inconvenience, and if it is not done the method loses its effectiveness. That is, the success of this method is dependent upon obtaining temperature readings regularly and upon proper interpretation of the recorded temperature information. Another method used by many females is the rhythm method. Although the rhythm method is one of the less effective methods of birth control, many females use this method because it conforms with their values. However, in many cases there are misunderstandings as to how the rhythm method is synchronized with the menstrual cycle, and this leads to misconceptions such as the ones that the highest risk of conception occurs just before and after menstruation.
In recent years, scientific approaches have been used to develop a way for predicting the woman's fertile period and the risk of conception. For example, an article by John C. Barrett and John C. Marshall entitled "The Risk of Conception on Different Days of the Menstrual Cycle" which appeared in Population Studies, Volume XXIII, No. 3, November, 1969, reports the results of a statistical analysis of data using a computer to correlate time of ovulation, frequency of coitus and the number of conception cycles. A mathematical function was developed which yielded the probability of conception on different days of the menstrual cycle. The study indicated that the risk of conception is small in the early part of the menstrual cycle. It increases noticeably about five days before ovulation and is maximum on the second day before ovulation. The risk of conception falls sharply by the second day following ovulation. The results of this study make it possible to predict high risk of conception times relative to ovulation. However, application requires use of the BBT method for the detection of the onset of ovulation.
A fertility indicator which obviates the need for using the BBT method has been developed for individual use by Reproduction Research Laboratories, Inc., Westport, Conn. The fertility indicator, which is a hand-held analog calculator, performs calculations of six variables affecting the optimal timing of sexual relations for conception. Although the device replaces basal temperature charts, which some couples find anxiety producing, the device is relatively expensive, and it would appear that medical counselling would be required to assure that the apparatus is used properly.